Re: postgres_fdw, dblink, and CREATE SUBSCRIPTION security

Jacob Champion <jchampion@timescale.com>

From: Jacob Champion <jchampion@timescale.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, Mark Dilger <mark.dilger@enterprisedb.com>, Jeff Davis <pgsql@j-davis.com>, Amit Kapila <amit.kapila16@gmail.com>, Andrew Dunstan <andrew@dunslane.net>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2023-04-12T18:23:01Z
Lists: pgsql-hackers
On 3/30/23 05:58, Robert Haas wrote:
> On Fri, Mar 24, 2023 at 5:47 PM Jacob Champion <jchampion@timescale.com> wrote:
>> Okay, but this is walking back from the network example you just
>> described upthread. Do you still consider that in scope, or...?
> 
> Sorry, I don't know which example you mean.

The symmetrical proxy situation you described, where all the proxies are
mutually trusting. While it's easier to secure that setup than the
asymmetrical ones, it's also not a localhost-only situation anymore, and
the moment you open up to other machines is where I think your
characterization runs into trouble.

> I guess I wouldn't have a problem blaming the DBA here, but you seem
> to be telling me that the security literature has settled on another
> kind of approach, and I'm not in a position to dispute that. It still
> feels weird to me, though.

If it helps, [1] is a paper that helped me wrap my head around some of
it. It's focused on capability systems and an academic audience, but the
"Avoiding Confused Deputy Problems" section starting on page 11 is a
good place to jump to for the purposes of this discussion.

--Jacob

[1] https://srl.cs.jhu.edu/pubs/SRL2003-02.pdf



Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →
  1. Fix possible crash in tablesync worker.

  2. Display 'password_required' option for \dRs+ command.

  3. Restart the apply worker if the 'password_required' option is changed.

  4. Fix possible logical replication crash.

  5. Add new predefined role pg_create_subscription.

  6. Expand AclMode to 64 bits

  7. More cleanup of a2ab9c06ea.

  8. Respect permissions within logical replication.

  9. Improve table locking behavior in the face of current DDL.